1. Field of the Invention
The present invention relates to a projector type vehicular lamp device applied as a head lamp and using a light emitting diode (LED) in a light source.
2. Description of the Related Art
FIG. 1 shows a conventional projector type vehicular lamp device 100 (for example, refer to a microfilm of Japanese Utility Model Application No. 4-76322 (Japanese Utility Model Application Laid-Open Publication No. 6-41010). The vehicular lamp device 100 comprises a light source bulb 2 provided near a first focus of a concave mirror 1, and a convex lens 3 modulating a light flux outgoing from the light source bulb 2 and reflected on the concave mirror 1 to an approximately parallel light flux so as to emit to a front side of the vehicular lamp device 100 (a left side in FIG. 1).
In detail, the vehicular lamp device 100 is structured such that a shade 4 is provided between the light source bulb 2 and the convex lens 3, and a light distribution pattern having a preferable cut line can be obtained as a beam for when vehicles go by each other (hereinafter, refer to as a low beam) by the shade 4.
The light source bulb 2 is structured such that a filament thereof is positioned at the first focus of the concave mirror 1, and an electric connecting portion thereof is fitted to a tubular opening portion 1a. A frame 5 is attached to an open end of the concave mirror 1, the convex lens 3 is firmly attached to the frame 5, and the frame 5 bears the shade 4.
Further, the vehicular lamp device 100 is structured, as shown in FIG. 2, such that a ventilating through hole 1b is provided in an upper side just near the tubular opening portion 1a for attaching the light source bulb 2 in the concave mirror 1, and a pair of ventilating through holes 1c are provided in a lower side just near the same, respectively.
A temperature of the vehicular lamp device 100 becomes generally high in the periphery of the light source bulb 2 at a time of lighting, however, since a heat generated by the light source bulb 2 is radiated on the basis of a heat convection generated between the through holes 1b and 1c, the temperature around the light source bulb 2 is inhibited from being increased.